Do you have instances of multiple relationships, such as double cousins, or pedigree collapse, in your family tree? If so, the new third-party DNA tool BanyanDNA can help you analyze the amount of DNA you share with your cousins.
Leah Larkin introduced Banyan DNA in December of 2023, and in that blog post she wrote:
BanyanDNA is unlike any other tool for genetic genealogy. Not only can it help you identify an unknown parent, grandparent, or great grandparent, it can alert you to places in your tree where shared DNA does not support the documented relationships. Best of all, it is completely customized to your family, whether you have pedigree collapse, double cousins, or (in a future release) endogamy.
If you’re confused about the terms multiple relationships, pedigree collapse, or endogamy, see my blog post Endogamy, Pedigree Collapse, and Multiple Relationships: What’s the Difference and Why Does it Matter? In that post, I share the example of multiple relationships in my family tree. My great-grandparents, Dock Harris and Alice Frazier, each had a sibling who also married each other, so descendants of these two couples are double cousins.
When the new tool BanyanDNA launched that could analyze these types of relationships, I created a tree using this scenario. Because Banyan allows you to add DNA matches between multiple test-takers, I was able also to add my first cousins and a first cousin once removed to the tree.
The Banyan tree is oriented horizontally instead of vertically, as in my diagram. In the tree below, you can see my great grandparents, John C. Harris and Malissa Welch, Richard Frazier, and Nancy Briscoe. You can see the same descendancy as in my diagram above. Notice also the additional cousins I entered ( Mary, John, and William).
With BanyanDNA, you can add DNA matches from any DNA testing company and add as many DNA connections as desired. Two of my cousins, John and William, have shared their Ancestry DNA with me, so I was able to see how much DNA each of them shared with our double cousins. The purple DNA icons indicate that I have entered DNA for those people.
Opening up the DNA side panel, you can see the data you’ve entered. Notice that I share more DNA with these double cousins than does John, my 1C, and William, my 1C1R.
To check the validity of our relationships and shared DNA, I next ran the calculation after adding myself as a hypothesis and received a “possible” in the relative probability column and a green in the quality column.
BanyanDNA gives this information about calculations.
In BanyanDNA, calculations are statistical evaluations of the DNA match data in your project. The BanyanDNA tool will simulate the inheritance of DNA from the earliest ancestors in the tree down to the people with DNA match data. Because DNA inheritance has a random component, BanyanDNA runs these simulations hundreds or thousands of times (called trials) to estimate the expected ranges of shared DNA for each pair of DNA testers. Then it will compare those expected (simulated) results with the actual shared DNA values to assess how well the DNA data aligns with the tree structure.
I enjoyed filling out this double-cousin tree and testing the relationships. If you are working with a case of complicated DNA, such as multiple relationships or pedigree collapse, you can learn to use BanyanDNA to identify unknown ancestors or to find places in your tree where the shared DNA is either too low or too high for the documented relationship.
To learn more about BanyanDNA, see the Quickstart Guide, which links to a video and also has written instructions.
Best of luck in all your genealogical endeavors!
4 Comments
Leave your reply.